Film scanning system having improved vertical stability

Claim 2

An electronic film scanning system comprising: film transport apparatus for conveying a photographic film at a substantially uniform rate past a scanning position said film having a succession of data bearing frames along the length thereof and a plurality of synchronization marks along the length thereof, there being a single synchronization mark associated with each frame; electronic scanning means operative to scan in a predetermined pattern each of said frames of said film as said film is conveyed past a scanning position; photodetector means for sensing light from said electronic scanning means transmitted by said scanned film frames and for providing an electrical signal in response thereto; video processing means operative in response to said electrical signal to provide an output signal representative of data contained in said scanned film frames; means for sensing said synchronization marks on said film and for providing output indications thereof; means for providing film synchronization pulses in response to said output indications; means for providing a reference signal at the power line frequency of said system; a dynamic framing circuit operative in response to said film synchronization pulses and said reference signal to produce a compensation signal for each frame, said compensation signal being representative of the time difference between said film synchronization pulses and said reference signal; means for applying said compensation signal to said electronic scanning means during each entire frame to maintain alignment between the scanning pattern of said scanning means and the scanned film frAmes; and servo control means coupled to said film transport apparatus and operative in response to the difference in phase between said film synchronization pulses and said reference signal to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency.

Claim 3

The invention according to claim 1 wherein said servo control means includes: means for deriving reference pulses from said reference signal; and means operative in response to said reference signal and said film synchronization pulses to provide an error signal representative of the time difference between said film synchronization pulses and said reference signal.

Claim 4

The invention according to claim 1 wherein said servo control means includes: means operative in response to said reference signal for providing a square wave signal at said power line frequency; means operative in response to said square wave signal to provide a ramp signal; means for storing a representation of the voltage of said ramp signal at the time of occurrence of each of said film synchronization pulses; and means for deriving a first error signal from said stored voltage representation to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency; and wherein said dynamic framing circuit includes: means for storing said representation of the voltage of said ramp signal; means for delaying said reference pulses by a predetermined amount; means for deriving a second error signal from said stored voltage representation at the end of said delay interval; and means for producing said compensation signal in response to said second error signal.

Claim 5

The invention according to claim 1 wherein said dynamic framing circuit includes: a plurality of logic gates operative to receive said film synchronization pulses and said reference pulses and operative to provide a first output signal when said film synchronization pulses lead said reference pulses, to provide a second output signal when said film synchronization pulses lag said reference pulses and to provide both said first and second output signals when said film synchronization pulses and said reference pulses are in time coincidence; means for providing a voltage representative of the difference in the time of occurrence of said film synchronization pulses and said reference pulses; and means for producing said compensation signal in response to said representative voltage.

Claim 6

In an electronic film scanning system having a photographic film containing a succession of frames of data along the length thereof, a film transport for moving said film at a substantially uniform rate past a scanning position, an electronic scanner for scanning each of said frames at said scanning position, and means for deriving an output signal representative of data contained in said scanned film frames, means for dynamically compensating for the effect of instability in said system and comprising: means for driving synchronization pulses from said film; means for providing a reference signal at the power line frequency of said system; means for deriving from said reference signal reference and vertical synchronization pulses at the frequency of said reference signal; a dynamic framing circuit operative in response to the difference in the time of occurrence of said film synchronization pulses and said reference pulses to produce a compensation signal for said electronic scanner to maintain alignment between the scanning pattern of said scanner and film frames being scanned, said dynamic framing circuit including a. means for applying said film synchronization pulses to first and second gates; b. means for applying said reference pulses to third and fourth gates; c. means for applying the output of said first gate to the input of said fourth gate; d. Means for applying the output of said third gate to the input of said second gate; e. an integrator operative to combine the signals received from said second and fourth gates; f. a sample and hold circuit operative to receive an output signal from said integrator; g. means for applying a sample signal derived from said reference pulses to said sample and hold circuit to cause storage of a voltage level related to said time difference; and h. means for producing said compensation signal in response to said stored voltage level; and servo control means coupled to said film transport and operative in response to the difference in phase between said film synchronization pulses and said reference signal to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency.

Claim 7

In an electronic film scanning system having a photographic film containing a succession of frames of data along the length thereof, a film transport for moving said film at a substantially uniform rate past a scanning position, an electronic scanner for scanning each of said frames at said scanning position, and means for deriving an output signal representative of data contained in said scanned film frames, means for dynamically compensating for the effect of instability in said system and comprising: means for driving synchronization pulses from said film; means for providing a reference signal at the power line frequency of said system; means for deriving from said reference signal reference and vertical synchronization pulses at the frequency of said reference signal; a dynamic framing circuit operative in response to the difference in the time of occurrence of said film synchronization pulses and said reference pulses to produce a compensation signal for said electronic scanner to maintain alignment between the scanning pattern of said scanner and film frames being scanned, said dynamic framing circuit including a. means for applying said film synchronization pulses to first and second gates; b. means for applying said reference pulses to third and fourth gates; c. means for applying the output of said first gate to the input of said fourth gate; d. Means for applying the output of said third gate to the input of said second gate; e. an integrator operative to combine the signals received from said second and fourth gates; f. a sample and hold circuit operative to receive an output signal from said integrator; g. means for applying a sample signal derived from said reference pulses to said sample and hold circuit to cause storage of a voltage level related to said time difference; and h. means for producing said compensation signal in response to said stored voltage level; and servo control means coupled to said film transport and operative in response to the difference in phase between said film synchronization pulses and said reference signal to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency.

Claim 8

An electronic film scanning system comprising: film transport apparatus for conveying a photographic film at a substantially uniform rate past a scanning position, said film having a succession of data bearing frames along the length thereof and a plurality of synchronization marks along the length thereof; electronic scanning means operative to scan in a predetermined pattern each of said frames of said film as said film is conveyed past a scanning position; photodetector means for sensing light from said electronic scanning means transmitted by said scanned film frames and for providing an electrical signal in response thereto; video processing means operative in response to said electrical signal to provide an output signal representative of data contained in said scanned film frames; means for sensing said synchronization marks on said film and for providing output indicatiots thereof; means for providing film synchronization pulses in response to said output indications; means for providing a reference signal at the power line frequency of said system; a dynamic framing circuit operative in response to said film synchronization pulses and said reference signal to produce a compensation signal representative of the time difference between said film synchronization pulses and said reference signal; means for applying said compensation signal to said electronic scanning means to maintain alignment between the scanning pattern of said scanning means and the scanned film frame; and servo control means coupled to said film transport apparatus and operative in response to the difference in phase between said film synchronization pulses and said reference signal to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency, said servo control means including a. means operative in response to said reference signal for providing a square wave signal at said power line frequency; b. means operative in response to said square wave signal to provide a ramp signal; c. means for storing a representation of the voltage of said ramp signal at the time of occurrence of said film synchronization pulses; and d. means for deriving a first error signal from said stored voltage representation to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency; said dynamic framing circuit including e. means for storing said representation of the voltage of said ramp signal; f. means for delaying said reference pulses by a predetermined amount; g. means for deriving a second error signal from said stored voltage representation at the end of said delay interval; and h. means for producing said compensation signal in response to said second error signal.

Claim 9

An electronic film scanning system comprising: film transport apparatus for conveying a photographic film at a substantially uniform rate past a scanning position, said film having a succession of data bearing frames along the length thereof and a plurality of synchronization marks along the length thereof; electronic scanning means operative to scan in a predetermined pattern each of said frames of said film as said film is conveyed past a scanning position; photodetector means for sensing light from said electronic scanning means transmitted by said scanned film frames and for providing an electrical signal in response thereto; video processing means operative in response to said electrical signal to provide an output signal representative of data contained in said scanned film frames; means for sensing said synchronization marks on said film and for providing output indicatiots thereof; means for providing film synchronization pulses in response to said output indications; means for providing a reference signal at the power line frequency of said system; a dynamic framing circuit operative in response to said film synchronization pulses and said reference signal to produce a compensation signal representative of the time difference between said film synchronization pulses and said reference signal; means for applying said compensation signal to said electronic scanning means to maintain alignment between the scanning pattern of said scanning means and the scanned film frame; and servo control means coupled to said film transport apparatus and operative in response to the difference in phase between said film synchronization pulses and said reference signal to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency, said servo control means including a. means operative in response to said reference signal for providing a square wave signal at said power line frequency; b. means operative in response to said square wave signal to provide a ramp signal; c. means for storing a representation of the voltage of said ramp signal at the time of occurrence of said film synchronization pulses; and d. means for deriving a first error signal from said stored voltage representation to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency; said dynamic framing circuit including e. means for storing said representation of the voltage of said ramp signal; f. means for delaying said reference pulses by a predetermined amount; g. means for deriving a second error signal from said stored voltage representation at the end of said delay interval; and h. means for producing said compensation signal in response to said second error signal.

Claim 10

An electronic film scanning system comprising: film transport apparatus for conveying a photographic film at a substantially uniform rate past a scanning position said film having a succession of data bearing frames along the length thereof and a pluraliTy of synchronization marks along the length thereof; electronic scanning means operative to scan in a predetermined pattern each of said frames of said film as said film is conveyed past a scanning position; photodetector means for sensing light from said electronic scanning means transmitted by said scanned film frames and for providing an electrical signal in response thereto; video processing means operative in response to said electrical signal to provide an output signal representative of data contained in said scanned film frames; means for sensing said synchronization marks on said film and for providing output indications thereof; means for providing film synchronization pulses in response to said output indications; means for providing a reference signal at the power line frequency of said system; a dynamic framing circuit operative in response to said film synchronization pulses and said reference signal to produce a compensation signal representative of the time difference between said film synchronization pulses and said reference signal, said dynamic framing circuit including a. a plurality of logic gates operative to receive said film synchronziation pulses and said reference pulses and operative to provide a first output signal when said film synchronization pulses lead said reference pulses, to provide a second output signal when said film snychronization pulses lag said reference pulses and to provide said first and second output signals when said film synchronization pulses and said reference pulses are in time coincidence; b. means for providing a voltage representative of the difference in time of occurrence of said film synchronization pulses and said reference pulses; and c. means for producing said compensation signal in response to said representative voltage; means for applying said compensation signal to said electronic scanning means to maintain alignment between the scanning pattern of said scanning means and the scanned film frames; and servo control means coupled to said film transport apparatus and operative in response to the difference in phase between said film synchronization pulses and said reference signals to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency.

Claim 11

An electronic film scanning system comprising: film transport apparatus for conveying a photographic film at a substantially uniform rate past a scanning position said film having a succession of data bearing frames along the length thereof and a pluraliTy of synchronization marks along the length thereof; electronic scanning means operative to scan in a predetermined pattern each of said frames of said film as said film is conveyed past a scanning position; photodetector means for sensing light from said electronic scanning means transmitted by said scanned film frames and for providing an electrical signal in response thereto; video processing means operative in response to said electrical signal to provide an output signal representative of data contained in said scanned film frames; means for sensing said synchronization marks on said film and for providing output indications thereof; means for providing film synchronization pulses in response to said output indications; means for providing a reference signal at the power line frequency of said system; a dynamic framing circuit operative in response to said film synchronization pulses and said reference signal to produce a compensation signal representative of the time difference between said film synchronization pulses and said reference signal, said dynamic framing circuit including a. a plurality of logic gates operative to receive said film synchronziation pulses and said reference pulses and operative to provide a first output signal when said film synchronization pulses lead said reference pulses, to provide a second output signal when said film snychronization pulses lag said reference pulses and to provide said first and second output signals when said film synchronization pulses and said reference pulses are in time coincidence; b. means for providing a voltage representative of the difference in time of occurrence of said film synchronization pulses and said reference pulses; and c. means for producing said compensation signal in response to said representative voltage; means for applying said compensation signal to said electronic scanning means to maintain alignment between the scanning pattern of said scanning means and the scanned film frames; and servo control means coupled to said film transport apparatus and operative in response to the difference in phase between said film synchronization pulses and said reference signals to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency.